Sockapalooozoops!

Well, I have a sock finished. It's lovely, I think, and very soft and warm and fuzzy. There is just one problem, but it's a killer: the ankle of the sock, knitted in the kid merino in the old shale lace pattern, has NO stretch to it--it will NOT go over my heel--even unrolled, even stretching beyond what's reasonable, even praying to the knitting gods, even when cursing under my breath.....my sock pal has about the same size feet as mine, so I think they (well, at this point, still it) will not fit her (well, they might, after she has used a shoe horn to stuff her heel through the ankle, but that hardly seems the most hospitable sock to offer someone! What I don't know is if this problem is because of the yarn, or the lace pattern, or the tension--though the rest of the sock (the cashmere part) seems fine. So I'm not sure what to do. I ordered some more of the cashmere; if the "Old shale" pattern is part of the problem, I may need to switch to something else, even if I add stitches. And I guess I will finish this pair of socks for a very skinny footed and ankled person! ANy thoughts out there on this pattern? (help!)